A Deduction of Carathéodory's Principle from Kelvin's Principle


THIS communication gives a simple deduction of Carathéodory's principle from Kelvin's principle that it is impossible to convert an amount of heat completely into work in a cyclic process without at the same time producing other changes. There has always been some difficulty in motivating Carathéodory's principle convincingly1. The present argument demonstrates for the first time that this principle can be obtained directly and simply from the impossibility of a perpetuum mobile of the second kind, and some reappraisal of the relationship between these two methods of developing thermodynamics appears, therefore, to be required.

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  1. 1

    Born, M., Natural Philosophy of Cause and Chance, 39 (Oxf. Univ. Press, 1949). Landsberg, P. T., Thermodynamics with Quantum Statistical Illustrations, 53, 61 (Interscience, 1961).

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  2. 2

    Planck, M., S.B. preuss. Akad. Wiss., 453 (1926).

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LANDSBERG, P. A Deduction of Carathéodory's Principle from Kelvin's Principle. Nature 201, 485–486 (1964). https://doi.org/10.1038/201485b0

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